Studying Facial Activity in Parkinson's Disease Patients Using an Automated Method and Video Recording

Abstract

Main objective of this research is studying facial activity of PD patients using an automated method for assessing facial movements based on calculating the movement signal kinematic characteristics. 16 PD patients and 16 participants in the control group have been recorded using 2D video camera while performing 4 facial tests: closing the eyes, raising the eyebrows, smiling with an effort (grin), moving the eyebrows. Each test includes a 10-fold repetition of a given facial movement with maximum effort and velocity. Intensities of the corresponding action units (AUs) in each frame have been determined by an automated method for each test. The resulting signal of the AU intensity dependence on the frame number has been marked with maximum and minimum points. From the extremum points, 11 kinematic parameters have been calculated for each AU of each patient. To assess the differences in kinematic parameters between the groups, the nonparametric Mann-Whitney test has been used. There is decrease in the facial movements frequency and velocity. Consequently, there is increase in the duration of the performance of facial tests in PD patients group compared to the control group. Only some AUs also showed a decrease in the amplitude of facial movements in PD patients group compared to the control group. Differences in the largest number of kinematic parameters have been obtained for the action units AU12 and AU14 recorded during the smile with effort test, and AU04 recorded during the eyebrow moving test.

Keywords

• parkinson's disease
• hypomimia
• action units